Problem: Express your answer as a mixed number simplified to lowest terms. $11\dfrac{3}{7}-7\dfrac{3}{4} = {?}$
Find a common denominator for the fractions: $= {11\dfrac{12}{28}}-{7\dfrac{21}{28}}$ Convert ${11\dfrac{12}{28}}$ to ${10 + \dfrac{28}{28} + \dfrac{12}{28}}$ So the problem becomes: ${10\dfrac{40}{28}}-{7\dfrac{21}{28}}$ Separate the whole numbers from the fractional parts: $= {10} + {\dfrac{40}{28}} - {7} - {\dfrac{21}{28}}$ Bring the whole numbers together and the fractions together: $= {10} - {7} + {\dfrac{40}{28}} - {\dfrac{21}{28}}$ Subtract the whole numbers: $=3 + {\dfrac{40}{28}} - {\dfrac{21}{28}}$ Subtract the fractions: $= 3+\dfrac{19}{28}$ Combine the whole and fractional parts into a mixed number: $= 3\dfrac{19}{28}$